At least in plasma-login-manager 6.5.91 (will test earlier versions soon), any activity besides typing a password does not reset the idle countdown. Say the login screen is in idle state, and you move the mouse to wake it up. It will go back into idle state ten seconds later *even if you move or click the mouse, or hit any key that doesn't count as password entry (e.g. tab), during those ten seconds*. It only will *not* go into idle state if you start typing a password. In fact, it appears to *never* go into idle state if the password entry box is active and contains characters. Combined with the change of the idle timeout from 60 to 10 seconds, this is extremely awkward for test automation.